Diving board



April 22, 1958 E. H. KNOX DIVING BOARD Filed oct. 14, 1954 1N V EN TOR.

rrapA/ey BY @MM C@ without doing damage thereto.

Unie rares Patent DiViNG EGARD Ervin H. Knox, Santa Monica, Calif.

Application October 14, 1954, Seriai No. 462,245

6 Claims. (Cl. 272-66) The present invention relates to the field of swimming pool accessories, and more particularly to a hollow core diving board that may be fabricated from water impervious material to the desired length, and the desired degree of resiliency for the selected length.

A major object of the present invention is to supply a light-weight diving board capable of being fabricated in either a single permanent color or multiple color, that may be either transparent, translucent or opaque, may be illuminated to have a decorative appearance at night, and does not deteriorate appreciably when exposed to the weather, salt spray or strong sunlight.

Another object of the invention is to provide a diving board construction that permits fabrication thereof in any desired length, the degree of resiliency of which is controllable at the time of manufacture.

A further object of the invention is to provide a diving board construction that not only permits the degree of resiliency to be determined at the time the board is fabricated, but what is particularly important in diving, a

board the degree of resiliency of which will remain disease carrying bodies may lodge, and a board that may be cleaned with an antiseptic solution from time to tim Yet another object of the invention is to supply a diving board that is provided with a non-slip upper surface that serves equally well to provide divers with a iirm frictional surface on which to run or walk, and a surface that does not appreciably change its frictional characteristics irrespective of whether the board is wet or dry.

These and other objects and advantages of the invention will become apparent from the following description of a preferred form and certain alternate forms thereof, and from the drawings illustrating those forms in which:

Figure 1 is a perspective view of a diving board ernbodying the invention disposed in an operative position by the side of a pool;

Figure 2 is a perspective view of the end portion of the diving board, and showing the internal construction of the preferred form thereof;

Figure 3 is an enlarged fragmentary vertical cross sectional view of the form of the diving board shown in Figure 2, and taken on the line 3 3 thereof;

Figure 4 is a vertical cross sectional view ofthe iirst alternate form of the diving board; l

Figure 5 is a vertical cross sectional view of a second alternate form of the diving board.

Figure 6 is a perspective view of a fragment of the preferred form of diving board in a downwardly deformed position; and,

Figure 7 is a diagrammatic side elevational view of the board showing it in its two maximum stressed vpositions. i l Referring now to the drawing for the general arrangep '2,831,688 Patented Apr. 22, 1958 ICC ment of the invention, it will be seen that the diving board D extends outwardly over a pool P in the customary manner. The board D as is normal with such devices is supported transversely on theV upper portions of two parallel laterally separated tubular members 10 and 12. Members 10 and 12 are supported in an elevated position above the ground surface 14 by pairs of uprights 10a, 12a, which uprights are connected to the members by 90"v pipe elbows 10b, 12b or other. rigid means suitable for this purpose.

The diving board D, whether it be the preferred form shown in Figures 2 and 3, or the alternate forms illustrated in Figures 4 and 5 is aihxed to the upper portions of the members 10 and12 by vertically disposed bolts 15 that extend downwardly through the board to engage same. t

In Figure 2, it will be noted that the diving board D while of uniform width, is not uniform as to thickness, but with the maximum thickness of the board being adjacent the supports 10 at the rearward vertical end wall 16, and the minimum thickness at the forward vertical end wall 18. Two slightly outwardly and inwardly taperi of the board is best seen in Figures 2 and 3. An elongate core 26is provided, preferably having the transverse cross sectionshown in Figure 2. Fabrication of core 26 in this shape is achieved by coating and impregnatingl an elongate strip of fiberglass mat inwwhich the fibers are both longitudinally and transversely disposed for reinforcing purposes, by means of a liquid polymerizable material. VThe resinous material used folfthis purpose is of a typefthat not only polymerizes to a hard,V resilient massgbut is of a natureto permitcontrolof vthe time in which it is transformed from Vthe liquid-to the solid state.

In .the formation of core, as well astheenvelopes, the fiber glass is coated and impregnated with such a liquid resinous material to which aV catalyst has been added, which catalyst causes theliquid resinous material to polymerize Vwithin a certain length of time after vaddition thereto. The core 26 in cross 'section includes two laterally separated vertically disposed legs 28 that have hori- Zontally disposedsupporting webs Silextending inwardly therefrom. The webs 30 .are slightly greater in Width than a number of other laterally spaced-parallel supporting webs 32 disposed inwardly therefrom. Both the webs 30 and 32 extend the length of diving board D.l Core 26 is obtained inthe above-described conguration by fitting the berglass impregnated with liquid resinous material ontoa suitable elongate form on which it is allowed to rest until the polymerization reaction is complete. `The resulting core is rigid, `yet resilient to th'eextent thatit will deform'in""the `direction of a downwardload impact exerted thereon, so long as the magnitude of such impact is kept below a certain maximum value and the core is restrained from expanding laterally within certain limits.V

Restraint ofrlateral core movement arising from a downwardly directed load impact is' achieved byproviding' an elongate iirst envelope 4t) extending the length. of the core and bonded thereto. Envelope Litt-ispositioned on the core by wrappinga rectangular mat of fiber glassof the type, previously described aroundvthe core lafter the iiber 1glass mat has been coated andimpregnatedwith a pclymerizable resinous material. The

envelope 40 is defined by slide walls 4Z, 42', a bottomV disposed edges of the webs .30 develop intocombined connecting and supporting member 34 of V-shaped cross section that have a lower apex portion 36. Each of the members 34 have two legs 34a and 34b that extend upwardly and outwardly from apex portion 36. The upwardly disposed edges of the connecting and supporting members 34 develop into the previously mentioned webs 32. Each of the apex portions: 36 develops into a horizontal flange 37, 4which llange is dened by two side edges 37a, 37b that taper forwardly and outwardly. Each ilange 37, reaches its maximum width at the forward extremity of the board. Core 26 and envelope 4% are bonded together by axing the anges 37 to the interior surface of bottom layer 44, and allxing the webs 30, 32 to the inner surface of the top layer 46.

A second envelope 50 that is pigmented to the desired `color is caused to overlie the first envelope 40, with this envelope actually delining the exterior side walls 24 and 24', and the side walls 24, 24' being connected by a top layer 52 and bottom layer 54. The second envelope 50 serves not only to add the desired color to the diving board, but to reinforce the envelope 40 against the stress to which it is subjected by sudden shock imparted to the board as will later be discussed in detail.

The top layer 52 of the second envelope has an elongate rectangular strip 56 of a plastic sheet material bonded or otherwise aixed thereto. The strip 56 has a sanded or otherwise roughened upper surface 56a that provides suicient frictional contact with the feet of the divers, that the possibility of slippage of divers on the board is substantially eliminated, irrespective of whether the board is wet or dry.

The internal structure of the diving board as above described has been found from experience to give most satisfactory results in that the resiliency of the board may be controlled at the time of manufacture by varying the thickness of the material forming the core 26 or in varying the thickness of the material forming the envelopes 49 and 50. The operating conditions that a diving board or whatever construction must satisfy are somewhat unusual. First, the board must be light in weight and sufficiently resilient to respond both to the weight impact of a child in diving, as well as to provide suicient, but not excessive resiliency when a comparatively heavy adult also dives therefrom.

In addition, due to the function it serves, a diving board is subjected to unusual strains as'it is first deflected downwardly to the position 62 (Figure 7) when a person dives therefrom, With the board then due to such deformation, and the resiliency of the material forming same, rebounding upwardly to the position of Figure 7 generally designated by the numeral 64. The deflected portion of the diving board D then vibrates between the two maximum positions 62 and 64, with swings of decreasingly less amplitud-e until the board comes to rest in the position shown in Figure l. The board D to successfully withstand the stresses to which it will be subjected as above described must be of such construction that it may deform substantially the same amount in rapid sequence in both an up and ldown direction Without rupturing or suffering from this deformation.

To 'more easily understand the novelty of applicants invention a longitudinal side section of the diving board is shown in Figure 6. When a person walks out toward the free end of the board or jumps or dives therefrom, the board will deform downwardly to the position 62 shown in Figure 7. Obviously, the reactive downward force imparted to the board by a person jumping therefrom will ycause a greater downward deection to the board than when a person is standing stationary on the free end thereof. During downward deformation of the board D, as may be seen in Figure 6, the rectangular strip 56, the top envelope layers 46 and 52, as well as the upper portion of the side walls 42, 42 and 24, 24' will tend to elongate under tension. It will also be seen 4 that the bottom 44 of the envelope 40, the bottom layer 54 of the envelope 50, the lower portion of the side walls 42, 42' and 24, 24 will tend to shrink or shorten, and as a :consequence these portions of the board will be under compression. Therefore, as the upper portion of the diving board is under tension and the lower portion thereof is under compression, there must be a longitudinally extending line of demarcation between these two opposing forces, identified by the numeral 60 in Figure 6, in which the board is under neither compression nor tension. This line 6) is normally referred to as a neutral axis.

The forces to which the diving board D are subjected as above outlined are longitudinally directed, and arise purely from deformation due to the loading borne by free end portion thereof. However, as the board is of hollow construction and the core 26 is bonded to the interior surface of `the envelope 40, the webs 30, 32, the side walls 23, and the ilanges 37 are also subjected to lengthwise stresses borne by those portions of the envelope 40 to which they are attached.

lt is well recognized that longitudinal stresses created in a particular portion of a beam by loading or impact are dependent on the distance between that specific beam portion and the neutral axis of the beam, and increase in proportion to this distance. rl`hus, in the case of the diving board of the present invention, when it is deflected to position 62 the maximum tensional stresses would occur at the surface of strip 56. Likewise, the greatest compressive force would be exerted on the exterior surfaceof the bottom layer 53 of the second envelope. Obviously, when the board D dellects upwardly to position 64, the stresses set up therein are opposite to those created by downward detlection thereof. When the board is in position 64, the bottom layer 54 and those portions of the board extending inwardly toward the neutral axis are under tension, and likewise the strip 56 and portions of the board extending downwardly therefrom are under compression. Due to non uniformity of design between the upper and lower portions of the transverse lcross section of the board D, a vertical shift in the position of the neutral axis may take place from that occupied when the board is at position 62 and when the board is at position 64. A s previously mentioned, after a person has jumped from the divingV board it will rapidly vibrate up and down upon sudden release of such weight between positions 62 and 64, with each swing therebetween gradually decreasing in amplitude, during which time the component parts forming the board are alternately subjected in quick succession to first compression and then tension.

When the diving board D is stressed in the above-described manner, both portions of the board most distantly situated from the neutral axis 60 tend to move inwardly thereto to relieve the tension or compression exerted thereon, and as a result, the hollow core 26 due to being attached thereto is stressed in a longitudinal direction. The core 26 is also subjected to compressive forces due to the tendency of the strip 56 and the bottom layer 54 to move inwardly toward one another.

' As such compression on the core 26 occurs, the core tends to tlatten out, and as may be seen in Figure 3, the webs 30 and 32 have laterally directed compressive forces exerted thereon by legs 34a and 3411. The compressive forces exerted by the legs 34a on the members 30, are transmitted therethrough to the legs 28 which legs 28 distribute these compressive forces on sidewalls 24, 42 and 24', 42'. The forces exerted by legs 28 counteract inwardly directed forces exerted on sides 24 and 42 by the top and bottom layers of the two envelopes 40 and 50 which tend to move together. Inward movement of their top and bottom members can only be achieved it they become greater in width, and consequently, shorter in the side Walls connecting same.

As the V-shaped connecting and supporting members 34 tends.y to assume a 'fore attened shape, which can only be .accomplished by anincrease in the angle A between legs 34a and 34b thereof, a portion of this compressive force is transmitted downwardly to the bottom layers 44 and 54 through flange 37. This downwardforce counteracts an upward force on 'the part of the bottom layers as they tend to move inwardly into a position closer to the neutral axis. It will be apparent from the above description that the core 26 must act as a column to maintain the resilient envelopes 40, 50, and member v56 of' the board D in the desired shape, and consequently acting as a column, legs r28, 34a, 34]; as well as webs 30 and 32 must be of sufficient thickness to withstand the compressive forces to which they are subjected Without buckling. In addition to withstanding the above mentioned vertically directed compressive forces, the core 26 must also withstand longitudinal compressive and tensional loading, whether applied steadily or by suddent impact.

The method of making the board D above described 'rst entails determiningv the length of board that is to project forwardly from lateral member l2 as shown in Figure l, then the desired degree of resiliency of the board, and of course, the color thereof, as wellv as any special ornamentation to be carried thereon. ly,` the board must be sufficiently strong to withstand the weight impact of the heaviest individual that will use same.

With this information, the internal structure of the core 26 may be determined, and is predicated iirst on the heaviest weight to which the board will be subjected after installation in order to gauge the force of impact the board would receive when a person of such weight makes a running dive from the free end thereof. The greater the impact load to which the board will be subjacted, the closer the spacing of the apex portions 36 must be to provide a core 26 capable of withstanding same. The degree of resiliency or springiness of the core 26 is progressively lessened by the number of envelopes encasing same, as well as by the thickness of the sheet material forming each envelope. It will be apparent that the ber glass content of the sheeting forming the envelopes, together with the resiliency of the plastic used in the sheeting, will materially affect the springiness ofthe board D. Although two envelopes 40 and 50 have been used to illustrate the structure of the board, a single envelope may be employed if it provides a board having the desired physical characteristics. Also more than two envelopes may be utilized to encase the core 26 to lend additional stiffness thereto if required. The second envelope 50 is normally pigmented to give the desired color to the finished board.

When a board is to be used for exhibition diving in the evening, the exterior envelope, in the present instance envelope 50, may be coated with, or include a fluorescent compound such as one of the metallic sulphides as a part thereof, which compound emits a particular colored flow when excited by black light, or the like. Likewise, an illuminated decorative effect may be achieved by using a light-conducting plastic material to form the strip 56, or a strip 56a that is sandwiched be tween strip 56 and top layer 52. A light-conducting material such as Lucite manufactured by Du Ront de Nemours Company of Wilmington, Delaware could be satisfactorily employed for this purpose. Whena strip of material 56a' is used, it must extend rearwardly to a source of light 70, which may be disposed at any convenient location adjacent the rearward portion of the board.

It will be apparent that the material from which the board is fabricated must embody such physical characteristics as to withstand sudden shock applied thereto, and capable of resisting deformation beyond the elastic limits Structuralthereof when the board is subjected to maximum stressing.

such, and the material from which -it is fabricated suiciently strong as to enable the` core to concurrently serve as a column that can assume eitherl downwardly or upwardly applied forces, yet withstand the compressive and tensional forces longitudinally exerted thereon. The wall thickness of envelopes 40a'nd 50 `must be suicient to permit the upper and lower portions of the envelopes to accept the longitudinally directed compressive or tensional forces alternately exerted thereon'. Also, the top and bottom layers of the envelopes must be capable of taking transversely directed tensional loading when the core tends to atten out and elongate under load. Webs 30, 32 and anges 37 must also be able to withstand both longitudinal andvertical compressive forces.

The stressingk to. which the component elements. comprising board D aresubjected is particularly severe in that the initial downward deformation thereof is immediately followed by a deformation of .almost like magnitude in the opposite direction, as shown at`64 in Figure A7. 'i

ln addition to the construction above described, it is possible to form a diving board D' as shown in Figure 4, having an envelope 70 of rectangular cross section that is maintained in this shape by means of a plurality of channel-shaped resilient members 72 extending the length thereof, each of which include vertical webs 74, an upper horizontal flange 76, and' a lowerhorizontal ange 78. Flanges 76 are bonded tothe rupper interior surface 8i) of envelope 70, while the lowermost flanges 78'are likewise bonded to the interior surfaces 84 and 84 of the envelope 80. For decorative color purposes, as well as reinforcement, a second envelope 86 may be extended around envelope 17 in the same manner as the exterior envelope 50 described in the preferred form of the invention.

The operation of the first alternate form of the invention (Figure 4) is substantially the same as outlined relative to the preferred form thereof. It will be obvious that in the rst alternate form, the internal core structure is not adapted to transmit laterally directed tensional or compressional forces with the same degree of eiciency achieved by the preferred form of the invention.

A second alternate form of the device is shown in Figure 5 that includes an integral, elongate, rectangular member 90 that has a number of spaced lengthwise ribs 94 extending downwardly therefrom, as well as two side walls 96 and 96'. This integral member 90 serves as a core for a single resilient envelope 98 encasing same. In this form of the invention, the integral core 90 is adapted to withstand substantially all tensional and compressive stresses developed during use of the board in the manner previously described, and as a result, the envelope serves largely to enclose the core, and takes relatively little compressive and tensional forces developed as the board deforms downward or rebounds upwardly as shown in Figure 7.

Although the form of the invention herein shown and described is fully capable of achieving the objects and providing the advantages hereinbefore mentioned, it is to be understood that they are merely illustrative of the presently preferred embodiments thereof, and there is no intention to limit same to the details of construction herein shown and described other than as defined in the appended claims.

I claim:

1. A lightweight diving board of a desired weight and resiliency, comprising in combination: a resilient elongate hollow envelope of rectangular transverse cross section in the shape of a conventional diving board and formed of a fibre glass mat in which the fibres thereof are bonded together by a water impervious polymerized resinous material; and a plurality of laterally spaced, longitudinally extending resilient members formed of substantially the same material as said envelope, which members are bonded to the interior surfaces of said envelope,

with the number of said members being such that in cooperation with the resiliency of said envelope the desired degree of springiness is imparted to said diving board.

2. A diving board as defined in claim 1 wherein said envelope includes two longitudinally extending side walls,

with each of said walls having two forwardly extending edges that taper inwardly toward one another, which taper causes the vertical cross-sectional area of said envelope to decrease from a maximum at the rearward end of said envelope to a minimum at the iorward extremity thereof, said side Walls on the rearward portion of said envelope being suiciently great that said side walls and said members on said rearward portion` of said envelope cooperatively impart rigidity to and support said board in a diving position, with the depth of said side walls forwardly of said rearward portion being such that said side walls and said members cooperatively provide a board portion of substantialresiliency.

3. A diving board as defined in claim 2 wherein said' members have a plurality of webs extending transversely therefrom that are bonded to the upper and lower interior surfaces of said envelope, with said webs being of suicient area to prevent said members from rnpturing said envelope when said board is subjected to stresses by a person diving therefrom.

4. A diving board as defined in claim 3 wherein said members are angularly disposed relative to the interior surfaces of said envelope and separated from one another by said webs.

5. A diving board as dened in claim 4 wherein said webs are disposed adjacent to said side walls and have longitudinally extending legs projecting downwardly therefrom that are bonded to the interior surfaces of said side walls for reinforcing purposes.

6. A diving board as defined in claim 5 wherein a second envelope is provided that encases said member contacting envelope and is bonded thereto for reinforcing purposes.

References Cited in the le of this patent UNITED STATES PATENTS OTHER REFERENCES styrene-glass ber combinations-reinforced plastics, Plastics Industry, August 1951, pp. 19-23. 

